Centrifugal separator



Patented Apr. 2, 1940. I v v I UNITED-STATES PATENT orFicE Hans Olof Lindgren, Appelviken, Sweden, assign or to The De Laval Separator Company,,New York, N. Y., a corporation of'New Jersey Application April 1, 1937, Serial No. 134,196 7 In Sweden April 4,,1936

4 Claims. (01. 233-22),

My'invention relates to centrifugal separators upper .part of a centrifugal bowl and the two dis- 7 of the type in which the two separated compocharge chambers. Fig. 2 is a section through a nents of a liquid are discharged from the cenpart of one of the parers. I trifugalbowl by means of stationary'disc-shaped In the neck 3 of the centrifugal bowl two disdischarge members or paring devices, concentriccharge chambers 4 and :8, for j skim milk and 5' with the bowls axis, and projecting respectively cream respectively, are arranged." The discharge into discharge chambers communicating respecchamber 8, which, in the ;.embodiment shown, is tively with the inner and outer separating zones arranged below the-discharge chamber 4, receives of the bowl. One advantage of this type of sepaseparated cream fromthe inner zone of the bowl. rator is that admixture of air (which takes place The discharge chamber 4 receives separated skim 10 to a great extent with tubular or snail-like parers milk from a channel 1 communicating with the or Skimmers as well as in the open type of cenouter or peripheral .zone of the bowl. Extending trifuge unprovided with parers or Skimmers) is into chambers i and 8 are stationary disc-shaped largely prevented in centrifuges provided with parers or dischargemembers 5 and 9 respectively. '5 disc-shaped parers provided with peripheral in- In chamber 4 there" is a rotating mass of liquid lets, which lead out the liquids in more nearly having the cylindrical level 6. In chamber 8 foamless state. Nevertheless, where such centhere is also a rotating mass of liquid, the level of trifuges are used for the separation of certain which hasa somewhat smaller radius than the liquids, particularly cream and skim mi1k,'a par level 6 in chamber 4. The chambers 4 and 8 tial re-mixing of the separated liquids may some-- are separated from each other by a radially pro- .20 times take place because of formation of froth jecting wall II which extends a considerable way when the stationary discharge member contacts inside said liquid levels. If the liquid in chamwith the rotating mass of liquid. As the specific her 8 is cream, it is very important that it shall gravity of the froth is considerably lower than not in the least degree leak over to the chamber that of the liquids, the'froth may deposititself :4. In the form of a liquid the cream cannot 25 as a more or less heavy layer on the liquid levels leak over, since the wall i'i extends suliiciently inthe bowl. Sometimes the layer of froth may far inside the possible innermost position of the' become very thick and it may overflow the edge cream level. In some circumstances, however, of the boundary wall between the two discharge froth may form in chamber 3 by the action of chambers, and then a partial 're-mixing will restationary member 9 upon the rotating cream 39 sult. .According to the present invention this mass, which froth deposits itself on the. liquid danger is avoided by," providing the discharge surface. The amount of froth may possibly so member for the froth-producing component with increase that it will overflow theedge of the wall axial channels, crossing the outlet channels for- 1 H and get into the chamber 4. In order to avoid the liquid and being positioned inside, or extendthis the member .9 is provided with a number of (35 ing a substantial distance inside, the liquid level. nearly axially directed channels I8 through which Through these channels the froth is conducted the froth may flow off to the chamber in the away from the boundary wall to the other side bowl situated below the member 9, where it is of the discharge member. The froth discharge distributed on the large liquid surface contained 40 channels should advantageously be provided with therein 'so that the air will gradually escape 40 I oblique edges which catch the rotating froth. therefrom. The chamber 8 is provided with radimass. In this way a kind of pumping action is ally arranged ribs IS in order to'insure that both produced upon thefroth mass, andit may there- .the mass of liquid and any froth present are in fore be said that the froth is pumped over from the highest possible degree caused to follow the the boundary Wall to the other side of the disrotation of the bowl. The froth mass is thereby 45 7 charge member. On that side of the discharge subjected to the influence of the centrifugal force member to which the mass of froth is pumped and is kept pressed on the surface of the liquid, a free space of considerable volume should be while the centrifugal force tends to separate the provided for such component, so that a liquid admixed air therefrom. The channels |8'- in surface of great extension is formed. As the member 9 should advantageously have rather 50 froth is there again brought into rotation, the large cross sections, so that the necessary amount air is ultimately separated, so that the froth is of froth can surely pass through. They should first reduced and then disappears. preferably also be oblique, so that they v(so .to Fig. 1, illustrating one embodiment of the inspeak) pare off the surface of the froth mass and vention, is a vertical sectional view through the thereby more easily conduct the froth to the 55 lower side of the member. At the upper orifice the channels should also be provided with an oblique edge formed by a lip or rim 20, which likewise has a paring effect on the froth mass and is'advantageous in regard to the above described pumping effect on the froth.

What I claim and desire to protect by Letters Patent is:

1. In a centrifugal separator comprising a rotatable bowl, means forming two discharge chambers adjacent each other and rotating with the bowl and communicating respectively with the outer and inner separating zones of the bowl,

said means including a partition closing one i chamber from the other except at the inner. ends,

disc-like paring devices within the respective chambers, and means to prevent froth formed in one of said discharge chambers from leaking to the other, said means comprising channels through the paring member in said froth-producing chamber, said channels being positioned nearer to the inner end than to the outer end of the paring member, the wall of each of the channels more distant from the axis of the bowl being, fromone end to the other, so much further from the center than the inner edge of said partition that substantially all froth accumulatinginside the level of liquid and on the side of the paring member facing the second of said chambers will be conveyed to the other side of the paring member.

2. In a centrifugal separator comprising a rotatable bowl, means forming two discharge chambers adjacent each other and rotating with the bowl and communicating respectively with the outer and inner separating zones of the bowl, said means including a partition closing one chamber from the other except at the inner ends, disc-like paring devices within the respective chambers, and means to prevent froth formed in one of said discharge chambers from leaking to the other, said means comprising channels through the paring member in said froth-producing chamber, said channels being positioned nearer to the inner end than to the outer end of the paring member, the wall of each of the channels more distant from the axis of the bowl being, from one end to the other, substantially further from such axis than the inner edge of said partition and thereby adapted to convey froth, accumulating inside the level of liquid and on the side of the paring member facing the second of said chambers, to the other side of the paring member, said means comprising also a lip at the rearward side, in direction of rotation of the liquid, of each channel, extending above the surface of the parer and providing an oblique edge to pare froth off the rotating mass and direct it into the channel.

3. In a centrifugal separator comprising a rotatable bowl, means forming two discharge chambers adjacent each other and rotating with the bowl and communicating respectively with the outer and inner separating zones of the bowl, said means including a partition closing one chamber from the other except at the inner ends, disc-like paring devices within the respective chambers, and means to prevent froth formed in one of said discharge chambers from leaking to the other, said means comprising channels through the paring member in said froth-producing chamber, said channels being positioned nearer to the inner end than to the outer end of the paring member, the wall of each of the channels more distant from the axis of the bowl being, from one end to the'other, substantially further from such axis than the inner edge of said partition and thereby adapted to convey froth, accumulating inside the level of liquid and on the side of the paring member facing the second of said chambers, to the other side of the paring member, said channels extending obliquely in the direction of rotation from the side of the parer nearer the partition to the other side of the parer to thereby pare off the surface of the mass and facilitate the passage of the froth through the paring device. I

4."In a centrifugal separator comprising a rotatable bowl, means forming two discharge chambers adjacent each other and rotating with the bowl and communicating respectively with the outer and inner separating zones of the bowl, said means including a partition closing one chamber from the other except at the inner ends, disc-like paring devices Within the respective chambers, and means to prevent froth formed in oneof said discharge chambers from leaking to the other, said means comprising channels through the paring member in said froth-producing chamber, said channels being positioned nearer to the inner end than to the outer end of the paring member, the inner edges of the mouths of said channels opening into the froth-producing chamber being not substantially nearer the axis of the bowl than the inner edge of said partition so that substantially the entire areas of the mouths of said channels opening into the froth-producing chamber are further from said axis than the inner edge of said partition, said channels being thereby adapted to convey froth, accumulating inside the level of liquid on the side of the paring member facing said partition to the other side of the paring member.

HANS OLOF LINDGREN. 

